The SMTP service HELP command must not be enabled on AIX.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-215417	AIX7-00-003122	SV-215417r508663_rule		Medium

Description
The HELP command should be disabled to mask version information. The version of the SMTP service software could be used by attackers to target vulnerabilities present in specific software versions.

STIG	Date
IBM AIX 7.x Security Technical Implementation Guide	2021-11-19

Details

Check Text ( C-16615r294702_chk )
Run the following command to get the "HELP" file location: # grep "^O HelpFile" /etc/mail/sendmail.cf The above command should yield the following output: O HelpFile=/etc/mail/helpfile If the above command does not yield any output, this is not a finding. The "HELP" file should be referenced by the "HelpFile" option. Check to see if the "HELP" file exists: # ls If the "HELP" file exists, this is a finding.

Check Text ( C-16615r294702_chk )

Run the following command to get the "HELP" file location:
# grep "^O HelpFile" /etc/mail/sendmail.cf

The above command should yield the following output:
O HelpFile=/etc/mail/helpfile

If the above command does not yield any output, this is not a finding.

The "HELP" file should be referenced by the "HelpFile" option.

Check to see if the "HELP" file exists:
# ls

If the "HELP" file exists, this is a finding.

Fix Text (F-16613r294703_fix)
To disable the SMTP service HELP command remove the HELP file using command: # rm